The objectives of this research project will be to study the genetic relationships between human varicella-zoster virus (VZV) and simian-varicella viruses as approached by nucleic acid renaturation experiments. In addition, the base sequence homology between VZV and herpes simplex virus (HSV), a human herpes-virus with many biological properties in common with VZV, will be determined by nucleic acid renaturation experiments. These experiments will entail the following: (1) Isolation of VZV, simian varicella virus and HSV DNAs by the Hirt procedure, (2) In vitro labeling of the DNAs in order to obtain DNA probes of high specific activity, (3) DNA-DNA renaturation experiments between the DNAs of VZV, simian-varicella viruses and HSV, and (4) thermal denaturation experiments of the reannealed products in order to measure the degree of homology between duplexes formed following renaturation.